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<h1><a name="C32"></a>Chapter 32: <a name="i0"></a>Singles</h1>
<p>
You have a grid of white squares, all of which contain numbers. Your task is to colour some of the squares black (removing the number) so as to satisfy all of the following conditions:
</p>
<ul><li>
No number occurs more than once in any row or column.
</li>
<li>
No black square is horizontally or vertically adjacent to any other black square.
</li>
<li>
The remaining white squares must all form one contiguous region (connected by edges, not just touching at corners).
</li>
</ul>
<p>
Credit for this puzzle goes to <a name="i1"></a>Nikoli <a href="#p0">[15]</a> who call it <a name="i2"></a>Hitori.
</p>
<p>
Singles was contributed to this collection by James Harvey.
</p>
<p><a name="p0"></a>
[15] <a href="http://www.nikoli.com/en/puzzles/hitori/index.html"><code>http://www.nikoli.com/en/puzzles/hitori/index.html</code></a> (beware of Flash)
</p>
<h2><a name="S32.1"></a>32.1 <a name="i3"></a>Singles controls</h2>
<p>
Left-clicking on an empty square will colour it black; left-clicking again will restore the number. Right-clicking will add a circle (useful for indicating that a cell is definitely not black).
</p>
<p>
You can also use the cursor keys to move around the grid. Pressing the return or space keys will turn a square black or add a circle respectively, and pressing the key again will restore the number or remove the circle.
</p>
<p>
(All the actions described in <a href="common.html#S2.2">section 2.2</a> are also available.)
</p>
<h2><a name="S32.2"></a>32.2 <a name="i4"></a>Singles parameters</h2>
<p>
These parameters are available from the &#8216;Custom...&#8217; option on the &#8216;Type&#8217; menu.
</p>
<dl><dt>
<em>Width</em>, <em>Height</em>
</dt>
<dd>
Size of grid in squares.
</dd>
<dt>
<em>Difficulty</em>
</dt>
<dd>
Controls the difficulty of the generated puzzle.
</dd>
</dl>

<hr><address>
[Puzzles S60 version 1.5.r9163]</address></body>
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